#include <stdio.h>
#include <math.h>
int main(int argc, char const *argv[])
{
    float a, b, c, s, area;
    printf("请输入三角形三边边长>:");
    scanf("%f%f%f", &a, &b, &c);
    // printf("a=%f,b=%f,c=%f", a, b, c);
    if ((a + b) > c && (a + c) > b && (b + c) > a)//三角形三边定理
    {
        s = (a + b + c) / 2;
        area = sqrt(s * (s - a) * (s - b) * (s - c));
        printf("area=%lf",area);
    }
    else
    {
        printf("不满足三边定理，请重新输入");
    }

    return 0;
}
